The present invention relates to coolers and particularly to cooling and freezing tunnel systems that impinge coolant onto a product for accelerated cooling and freezing thereof.
Many industries, not least among them the food industry, find it necessary in the course of their operations to be able to chill or freeze products relatively rapidly. Whether the product needing chilling or freezing is at room temperature, or is at temperatures higher than room temperature as the result of a previous processing or cooking step, reducing the temperature of the product rapidly is desirable in order to minimize the ability of pathological organisms such as bacteria to grow on or in a product, and (particularly when the product is to be frozen), to put the product into condition to be packaged prior to its being stored and/or shipped to distributors or customers. Examples of products which benefit from this treatment, which are also products that can be treated by the present invention, include raw foods such as eggs, hamburger patties, fruits and vegetables, raw or cooked cuts of meat such as beef, pork, veal, lamb, poultry carcasses and poultry sections, as well as processed foods prepared by combining various ingredients, such as pastries, pre-packaged entrees and complete dinners.
Many techniques are known for cooling and freezing such products. Examples include impingement coolers, mechanical refrigerators, and other devices wherein the product is conveyed through a chamber wherein the product is exposed to low temperatures for a sufficient period of time to reduce the temperature of the product to the desired final, cooled temperature.
Impingement coolers are one satisfactory mode for providing the desired rapid cooling or freezing. However, to date they have suffered from various drawbacks to completely efficient operation. In particular, the cold air or other coolant after it is impinged upon the product is either wasted or is recovered, recooled and recirculated to be impinged again upon additional product via structural configurations that interfere with the ability to provide satisfactory impingement upon the product for a suitable distance and length of time.
Thus, there remains a need for a device that provides more efficient impingement cooling and freezing, without unduly increasing the size of the apparatus employed to achieve a given amount of cooling or freezing.
One aspect of the present invention is a cooling tunnel comprising:
(A) conveyor means for carrying objects through said cooling tunnel;
(B) refrigeration means for receiving cooling fluid, chilling it, and providing chilled cooling fluid into said tunnel;
(C) at least one impingement section means extending along a portion of the length of said conveyor means within said cooling tunnel, there being one or more regions along the length of said conveyor means within said cooling tunnel along which no impingement section means extends,
each impingement section means comprising a plurality of channeling means arrayed parallel to the direction of motion of said conveyor means, adjacent ones of said channeling means defining therebetween an aperture for enabling cooling fluid to flow through said aperture toward and onto objects on said conveyor means, wherein said aperture is on an axis parallel to the direction of motion of said conveyor means, each said channeling means defining with said conveyor means a channel for receiving cooling fluid that has passed through an aperture onto said objects and for enabling said cooling fluid to flow into one or more of said regions;
(D) duct means for enabling flow of cooling fluid from one or more of said regions to said refrigeration means;
(E) passage means in fluid communication with an aperture and extending from said aperture into or across one of said regions, for enabling cooling fluid that enters said passage means from said aperture to enter said duct means after having flowed out of said passage means toward and onto said objects; and
(F) fan means for causing flow of said cooling fluid from said refrigeration means through an aperture with sufficient velocity to impinge upon and cool said objects and to recirculate said cooling fluid through said duct means to said refrigeration means.